5haan_A

Hi guys,

Firstly, a big thank you for contributing to helping to understand why those star shapes could occur. 

I had a look at two random light frames that I captured. These frames have had some preprocessing done namely flat and dark subtraction. I think they present another twist in the story, because they don't seem to contain the same star shape as what the final stacked image showed, which leads me to believe that the problem occurred during the stacking.

What do you guys think? Does it rule out some of the potential problems that have been identified in this thread?

Attached are two light frames taken in .fit format

Best,

recon_norm_pproc_L_2019-11-18_20-30-30_Bin1x1_120s__3C.fit recon_norm_pproc_L_2019-11-18_21-30-13_Bin1x1_120s__2C.fit

Hi,

Was imaging last night and whilst processing images I noticed this weird star shape when I zoomed in. It's something I didn't see when previewing the images whilst they were being captured because at first glance the stars seemed quite round. Is this some sort of tracking PHD 2, or PA issue? Usually when I have had PA issues my star shapes are much more linear, that's to say there is a bloat on one edge of the star. 

Attached is a PHD2 log fire as well

PHD2_GuideLog_2019-11-18_1954556.txt

Hi Guys,

Encountered an interesting problem. Where in a nutshell I can't seem to focus when when using 1 x 1 under the binning section of APT. I can focus when binning 4 x 4 but not 1 x 1. It's not an issue of not being able to focus, as I have a lakeside focuser and there isn't a point at which its more in focus, trust me I checked. Funnily enough, when set to 4 x 4 bin there are no focus issues and the images are quite sharp. 

I have attached an image of what I mean, its titled cave nebula, the title is the only place you'll see the cave nebula in the image. The second image I have attached is of bodes nebula using the same set up but on a previous night. Whilst not perfect you can see it's much better.

My question is really am I using the wrong settings? Should I be happy binning at 4 x 4 and getting a clearer image but with perhaps less fine detail. Could my settings be more refined for the set up I have?

The set up I have:

Mount: EQ6 pr0

OTA: Esprit 100

Camera: Zwo 294 MC cooled 

Capture: APT

Thanks,

cave nebula.fit Bodes nebula2.fit

Hi,

Colour processing question here. I am capturing using one shot colour CCD a ZWO 294 pro. I am finding it difficult to get the colour to show whilst processing the image. I am still capturing data on the cluster Caroline's Rose so I don't have anywhere near enough data yet to say it's complete, but I thought I would have a play around with some of the data captured last night. Out of the 30 120 second light frames only 2 of them are ok- it was v cloudy last night. 

I have attached one 120 second light frame of Caroline's rose, I haven't applied any darks or flats yet, I just wanted to see what it would look like after I debayered it in Nebulosity 4. 

Firstly it turned a sickly blue, and after adjusting the hue I was left with a very black and white looking image. I could maybe pick out some blue stars at a push, and definitely couldn't pick out any red stars. 

What am I doing wrong, and how do I improve the colour brought out in processing?

L_2019-10-14_00-52-26_Bin1x1_120s__11C.fit recon_L_2019-10-14_00-52-26_Bin1x1_120s__11C.fit

4 minutes ago, RolandKol said:

In your place, I would not, as the Calibration procedure succeeded, so the next step, - guiding and Imaging.

If you will be happy with the imaging results, - why should you spend any time on adjustments to make some red/blue graph look nice?

The end result is what matters.

P.S.

If you will run into guiding guiding problems, and you probably will, - you will need to improve the Guiding, not the calibration itself

100% agree with that sentiment. We astronomers can sometimes spend too long looking down rather than looking up.

Thanks 

5 hours ago, RolandKol said:

For Skywatcher Mount like HEQ5 or NEQ6, - it is good (not perfect).

For something like Mesu200, - not really good at all...

depends what you've got.

I have an eq6 mount so I'll take that. What are the steps I can take to improve the calibration? 

Thanks for the replies. I felt there was a little bit of the answer in everyone's replies.

The analogy that makes sense to me is that the rotation of the mount in RA is akin to a compass that you used to use in maths class. Once the software figures out, platesolves, where the pole star is it can figure out how far away your mount is from the that centre and then you adjust accordingly. The fact that your guide scope is pointing in a slightly different direction to your mount is not relevant to the software calculation. 

To some extent that makes sense to me.

Had another crack calibrating tonight. Got to something a little bit more acceptable. 

This is more what I after isnt it? I'm not familiar with what acceptable calibration data looks like but I'm assuming because I got no warnings and I did more than 2 steps this is better.

To be honest I dont have a smart way of how the above happened. I used my newer laptop, installed all the astro software and it just seemed to work straight out of the blocks. I'm not complaining.

10 minutes ago, michael8554 said:

possibly a cabling problem.

What kind of cabling problem could it be? 

4 hours ago, RolandKol said:

Now, we all know were your home and astro rig is based... (paint the coords off from EQMOD pic)

Wow. Would you believe it but I actually just realised of the back of your comment that I had typo'd the coords wrong into eqascom 😂

It might not be causing me to calibrate phd2 with 2 steps, but it certainly wont be helping my situation to have it wrong in there.

Best,

Hi,

It's a silly question in many ways, but I wanted to know why it works. Why can you polar align with your guide scope attaced to your OTA even if its not pointing at the exact same thing as your main OTA? I would have thought that you would only be able to PA with your main OTA on your mount. 

Thanks,

Hi,

I'm sure I must be doing something simple quite wrong, but I can't seem to figure out what the problem is.

The problem is that when running a calibration routine with PHD2 it finishes after completing just 2 steps East, west, north and south. Instead of taking the recommended 12. What this means is that I can't guide at all using PHD2, which is really stopping me from taking long exposures. 

To date I have tried reinstalling PHD2, following most of the best practice guide, I have changed the RA side reel rate in EQASCOM regardless of whether I use 0.1 or 0.9 it always does a 2 step calibration and even went as far as reinstalling windows completely. Nothing has worked. 

When calibrating I try and keep the DEC to around 20 or below, its hard where I live to get to 0, furthermore I am polar aligning fine using sharpcap so PA is usually rated good or excellent depending on my patience. 

Here are some screenshots to show what I have going on in the settings. 

Also, I have attached some log files from last night. They don't show much but do show that its calibrating in 2 steps. 

Equipment wise:

EQ6-Pro mount

ZWO 120 mm guide cam 

Evoguide 50 ED guide scope

Thanks,

PHD2_GuideLog_2019-10-09_231849.txt

Here is a stacked version of the image before any processing.

m51_01092019.fit

4 hours ago, Neiman said:

Haven’t taken an image yet as just started - but I’d be proud of that as a first image.

Thanks. I do feel proud. I was showing some people in the office today and there was a bit of head scratching going on when people were getting their heads around how it was possible to get picture of a galaxy. I was more than happy to explain.

4 hours ago, alan potts said:

For starting out I would have personally picked a star cluster or a globular cluster. M13 is a nice large one where you can see plenty even with limited data, don't try an be as good as some of the people on here straight away, what they do is superb but very difficult to get to the standard they are at and takes time, step by step. I tell you I not great but I have fallen from a few steps, all of this AP can cause even the best imagers problems, don't forget conditions are changing all the time which will not help.

I'll try make my life easier and focus in on something a little easier next time.

Thanks for that incredibly insightful advice Vlaiv. There's a lot to chew through with your post, but I'm going to work through it. I like the idea of switching to GIMP, it seems very powerful and that post you shared seems very helpful. I had used some flats in the pre processing, however I think that the dust particle in the equipment must be new. 

 I'll share the stacked .fit file when I get back home and see if there was more that can be pulled out from the data.

I have some questions on post processing. 

How do I get rid of that circular thing in the bottom left section of the image. Its quite dark but it's there. 

Theres also a blue squiggle near the bottom right of the galaxy, how do I get rid of that? I dont think it would have dark subtracted because it was in one of my lights. 

Where do you guys think is the best place to finish off an image, I was using nebulosity and lightroom. I didn't mind nebulosity too much, but with light room I had to convert the .fit file to .jpg before doing a histogram stretch etc.

On the histogram stretch is there some material that explains it well? Perhaps a book that's dedicated to post processing astro images.

Colour, I shoot using a colour camera, because I had thought that it would mean my images would look like the ones NASA Hubble telescope produces with all that vibrancy. My images started with a sickly glow that I could only reduce slightly. What's the best way to bring out colour in an image.

How do I make the background black? 

Thanks for the feedback.

6 hours ago, JamesF said:

For a first image, I think that's very good indeed.

If you're worried that focus might not be spot on, try a Bahtinov mask.  You can buy them, but it's quite possible to make one yourself from a sheet of card or plastic.  I 3d print mine (have one on the printer just finishing off at the moment, as it happens).

If you're happy with your guiding then I'd try for some longer exposures I think.

James

Thank you. I'll look into the mask. I think I saw that FLO are selling some reasonably priced ones. Although it would be cool to 3D print one of my own.

2 hours ago, alan potts said:

Yes nice first image, I think I may have picked something easier though, never easy any galaxy. As James said try a bit longer exposures.

Alan

Thanks. Any suggestions on an easier target? 

7 minutes ago, michael8554 said:

Yes, you have to have a star to be able to Calibrate ! But I've only got a budget ASI 120MM guidecam, even that finds stars everywhere, what have you got?

Yeah we have a similar camera. No problem with picking up  star in it. It's more a logistical one I cant see anything at that level due to terrain and a house. Would you say it would be worthwhile taking the set up to a different site where I can calibrate at 0 DEC?

Don't worry about being too hard, I know you're only trying to help. 

Best, 

59 minutes ago, michael8554 said:

I don't think you read and applied any of  the "Best Practices" written by the PHD2 developers that I gave you a link to ?

PHD2 usually recommends exposures between 1 and 3 seconds,  you've actually gone up to 4 secs - was that a Guiding Assistant recommendation ?

We're all trying to help you but you don't seem to be listening.

Michael

 

It literally says on the third page use loops of 2-4 seconds. What can you do if the only star you can calibrate on is around 20 DEC? 

I'll change the guide speed and increase the speed.

As I said in my post, I did manage to guide. I'm not sure how, but it did work, however I'm glad to hear that it could guide better. 

Thank you for your help Michael.

So I have finally managed to put together my first image. I'll be honest its been very tough, and the results are far from perfect. Since around April I have tried and tried some more to get all the equipment working to a point where I could put something together. First there was the software to get my head round. Then there were the guiding issues, and then after all of that there were things like darks, flats and bias to think about. I bought some books did some reading and finally got to a point where I could have some first attempts. 

My initial sessions were thwarted by issue after issue. Firstly polar alignment was much harder than I initially thought, that was until I found out about sharpcap. For guiding I use PHD2 and that wasn't easy to get right. Essentially there was four months of non stop problems and learning from them to get to a point where I could realistically get an image.

The below was shot using:

Scope - Esprit 100 

Mount -  EQ6 Pro

Camera - ZWO 224 MC

Guide- ZWO 120 mini

Software - EQmod, Cartes du ciel, APT, Nebulosity 4 and some lightroom to finish off

First image is of the Whirlpool Galaxy. It's the first time I managed to throw it all together with some success. My focus isn't great, the guiding could be better, and the image composition leaves a lot to be desired, but I'm happy because the last four months are finally bearing some fruit. 

Feedback is more than welcome, I really do want to improve. I can't wait to see where I will be a year from now. 

I used 20 45 second lights and 15 45 second darks. 

Just now, Thalestris24 said:

I thought you had a belt drive?

 

I do indeed.

5 hours ago, Thalestris24 said:

Hi

You should show your star profile and bullseye target from the view menu. The calibration doesn't look too good for a belt drive. Maybe guide scope flex or a balance issue.

Louise

Hi Louise,

Plenty of room for improvement for sure.

I was running the guiding with a slightly unbalanced scope so to engage the RA gears more, I'll try a more balanced set up next time and see if the numbers improve.

Best,

Shaan

So last night I had some success finally. I basically took on board everything that has been said in here and managed to guide with PHD2!

I made sure that my PA was as good as could be. 

I reinstalled PHD2 and recalibrated. I have attached the calibration data. I still wasnt happy that I got an orthogonal error of 14. PHD2 was saying that it should be below 10, but it was close enough.

I then managed to guide without major hiccups. I have attached some log data also. The only issue I had throughout the session was the images PHD2 were taking were variable. There was some sharp images were the stars were all visible through the findersope and it was happy, and there was some dim images were all but the brightest stars through the finder would disappear. This meant that there was significant star mass change from frame to frame. Not ideal but it meant that PHD2 would lose sight of the star for let's say 1 frame in three. It would pick it back up again the frame later so it was actually fine and didn't affect the session too much. 

Anyway thanks for the help, and if any of the info I provided can be used to give some more feedback it would be appreciated. 

On 27/08/2019 at 19:08, Hughsie said:

David has created a step by step guide to setting up platesolving in APT. Worth a look to get a feel as to what you need.

I just wanted to say thank you for sharing this with me. I followed the instructions step by step last night. 

Suffice to say I felt like a wizard. It worked perfectly and has made my sessions substantially easier. After doing it with plate solving I now cant see any other way of doing it. 

14 hours ago, Freddie said:

Are you sure your PA is good?

There are some interesting comments about Dark Frame on the forum that would be worth reading.

Yeah my PA was good. Did it in sharpcap until it said excellent, which for those that have used sharpcap to to PA takes some patience to get to.

I had a read just now about what some people have experienced with Darkframe optics. I must say my experience over the phone doesn't match up with what was said. Dave and I spoke for a good 20 minutes and he was more than helpful. Admittedly I haven't sent a scope to him so I cant comment on the full service.

8 hours ago, Photosbykev said:

I used the built in 'guiding assistant' wizard to fine tune my guiding. It suggested a few minor parameter tweaks that certainly improved the guiding for me

What kind of tweaks were these? 

5 hours ago, Anthonyexmouth said:

Are you calibrating every time you set up?

Unfortunately yes, until I build a pier. 

On 28/08/2019 at 09:22, david_taurus83 said:

What guide scope are you using?

I'm using a zwo 120 mini. I must add that this set up has worked perfect fine in the past with no issues. 

On 28/08/2019 at 14:57, Thalestris24 said:

I'd repeat calibration just in case. Another possibility is the belt tension allowing slippage. I would expect a new mount to be good to go but you never know. Power/connections maybe another source - are you using mains power? You don't say what scope you have? I assume you aren't over the 20kg payload limit...

Louise

I'm going recalibrate again this weekend when I have the time to move the set up to a suitable location to see some stars at the right DEC to calibrate. 

Power wise there are no issues. The battery I use has been great in the past and it supplies the right voltage for a good amount of time, I have never managed to run out of juice. 

I'm using an esprit 100, it's reasonably heavy, but well within the capacity for what the mount should handle.

I had a very good chat with a chap from dark frame optics today. They service skywatcher mounts and can tune your mount up. His suggestion was that my mount may either be too tight, as it is quite new, or a number of other issues that arent too bad. 

I'm hoping that the problem is software related and not hardware. I'm going to try and get as much data as I can out of PHD2 and share it on here and with the helpful chap from Dark Frame Optics with the hope that I may be able to get some sort of solution.